User friendliness of computers continues to be enhanced by better user interfaces. User interfaces for computers systems have evolved significantly since the personal computer (PC) first became widely available. Early PCs used rather primitive user input devices, where a single keyboard was the only human input mechanism. The vast improvement in microprocessors, available memory, and programming functionality have all contributed to the advancement of user interface designs and the development of user friendly graphic based operating systems and hardware.
One particular area of advancement in user interface technology pertains to surface computing technology. Surface computing allows any number of users to interact with a computer through an interactive surface. The computer can render a graphical user interface (‘GUI’) on the surface and multiple users may manipulate GUI displayed “objects” directly with their hands using multi-touch technology as opposed to using traditional input devices such as a mouse or a keyboard. In such a manner, the devices through which users provide input and receive output are merged into a single surface, which provide an intuitive and efficient mechanism for users to interact with the computer.
As surface computing becomes more ubiquitous in everyday environments, readers will appreciate advancements in how users may utilize surface computing to intuitively and efficiently perform tasks that may be cumbersome using traditional input devices such as a keyboard and mouse. More specifically in this case, the advancement pertains to the detection of something near an interactive surface, which is sometimes referred to as proximity detection. Generally, as applied to user interfaces, proximity detection is thus concerned with the detection of various gestures and/or multiple objects, including inanimate objects and persons, through the use of a user's hand or finger, for example, when in proximity of a user interface or surface. Such a system is commonly referred to as a multi-touch interactive system. Such a system can include a touch screen, touch tablet or touchpad that recognizes multiple simultaneous touch points and typically has software to interpret such simultaneous touches.
There are several detection technologies that may be utilized for proximity detection in connection with a user interface, including capacitance-based systems, infrared, and various optical-based detection systems. Optical-based proximity detection techniques have been developed that provide for illuminating an entire user interface surface with light and employ a digital video camera to recognize objects that are either in contact or proximate to a graphic display surface, based upon the light reflected from the objects. Interactive surfaces also allow for file sharing where the contents of a file can be projected to each user. The ways to detect objects and share files could be improved if there was better coordination between participants using the interactive surface or proximate to the interactive surface as only limited coordination capabilities exist.